Compressor

ABSTRACT

A compressor for compressing coolant circulating in a cooling circuit, wherein the compressor includes at least one receiving element for spring elements carrying a compressor/motor unit. With its casing element, this receiving element protrudes past a sump height of a lubricant sump in a vertical direction, which lubricant sump forms in the housing interior in an operating state of the compressor. Because lubricant is constantly distributed throughout the entire housing interior in the operating state—caused by the motion of the movable parts of the compressor—lubricant also collects within a receiving volume of the receiving element, where it forms a level that is clearly above the sump height of the lubricant sump as viewed in a vertical direction. As a result, a damping of the spring elements is achieved by the lubricant, and therefore without the inclusion of additional means elements.

FIELD OF THE INVENTION

The present invention relates to a compressor for compressing coolantcirculating in a cooling circuit, comprising a compressor housingenclosing a housing interior of the compressor,

-   -   a compressor/motor unit which comprises at least one piston,        which moves in a cylinder, and a motor,    -   at least one spring element, preferably multiple spring        elements, via which spring element the compressor/motor unit is        attached in an elastically mounted manner to a mounting region        of the compressor housing, preferably to a base region of the        compressor housing,    -   at least one receiving element arranged on the mounting region        for the at least one spring element, preferably one receiving        element for one spring element each, wherein the respective        spring element is accommodated in the receiving element, wherein    -   the receiving element comprises a base element, which is        connected to the mounting region and from which the spring        element protrudes in a vertical direction, a casing element,        which casing element surrounds the spring element in a        sleeve-like manner, and a receiving volume bounded by the base        element and the casing element, in order to enable a collection        of lubricant in the receiving volume, so that a section of the        spring element that is arranged in the receiving volume is        enveloped by lubricant in the operating state of the compressor.

PRIOR ART

In generic compressors according to the prior art, it is a well-knownproblem that the vibrations caused by the compressor/motor unit aremainly transmitted to the compressor housing of the compressor viaspring elements, by means of which the compressor/motor unit is mountedon the housing interior of the compressor. The greater the portion ofvibrations transmitted undamped to the compressor housing, the higherthe overall noise emission of the compressor.

Enhancements to known compressors with regard to a reduced noiseemission are aimed, for example, at a damping of said vibrationtransmission in the region of the spring elements. However, it isthereby disadvantageous that special damping elements are oftennecessary in this case, which by their very nature are exposed to highloads and thus wear out over the long term.

In this context, it was observed that means which are already present inthe housing interior of the compressor in the operating state of thecompressor can also be used to damp the vibration transmission. Inparticular, it was determined that spring elements that are covered tothe greatest possible extent by a lubricant sump present in the baseregion of the compressor housing during the operating state of thecompressor only transfer to the compressor housing a very small portionof the oscillations caused by the compressor/motor unit. The viscosityof the lubricant sump, which is formed mainly from oil and coolant,results in a damping of the spring elements surrounded by lubricant.

However, particularly the arrangement and position of the motor of thecompressor/motor unit inside of the housing interior constitute factorsthat have a limiting effect on the height of the lubricant sump level.The endeavor to reduce the noise emission of the compressor using ahigher lubricant sump level is thus opposed by the requirement of notimmersing the rotor of the compressor/motor unit in particular in thelubricant sump.

OBJECT OF THE INVENTION

It is therefore an object of the present invention to provide acompressor that enables an improved damping of the spring elements andthe accompanying vibration transmission to the compressor housing.

DESCRIPTION OF THE INVENTION

The object is attained with a compressor according to the invention forcompressing coolant circulating in a cooling circuit, comprising

-   -   a compressor housing enclosing a housing interior of the        compressor, a compressor/motor unit which comprises at least one        piston, which moves in a cylinder, and a motor,    -   at least one spring element, preferably multiple spring        elements, via which spring element the compressor/motor unit is        attached in an elastically mounted manner to a mounting region        of the compressor housing, preferably to a base region of the        compressor housing, and    -   at least one receiving element arranged on the mounting region        for the at least one spring element, preferably one receiving        element for one spring element each, wherein the respective        spring element is accommodated in the receiving element, wherein        the receiving element comprises a base element, which is        connected to the mounting region and from which the spring        element protrudes in a vertical direction, a casing element,        which casing element surrounds the spring element in a        sleeve-like manner, and a receiving volume bounded by the base        element and the casing element, in order to enable a collection        of lubricant in the receiving volume during operation of the        compressor, so that a section of the spring element that is        arranged in the receiving volume is enveloped by lubricant,

in that the casing element protrudes past a sump height of a lubricantsump in a vertical direction, which lubricant sump forms in the housinginterior during operation of the compressor.

When the compressor is in operation, during which the compressor isoperated as intended for the compression of coolant, the lubricant sumpforms in the housing interior, or more precisely in the base region ofthe housing interior. Usually by means of a crankshaft that is driven bythe motor of the compressor/motor unit for the purpose of compressingcoolant and extends sectionwise into the lubricant sump, lubricant istransported out of the lubricant sump in the direction of thecompressor/motor unit in a manner known per se, in order to lubricate,among other things, a crankpin of the crankshaft, a connecting rod thatproduces an operative connection between the piston and crankpin, abearing in which the crankshaft is mounted, and/or a cylinder wall ofthe cylinder, for example. The lubricant then drains out of thecompressor/motor unit and is in this manner fed back to the lubricantsump.

The receiving element according to the invention, which internallyaccommodates the respectively paired spring element sectionwise for thepurpose of tethering the same to the compressor housing, in particularto the mounting region of the compressor housing, enables the level ofthe lubricant to be increased in the respective region of the springelement without the need to raise the level of the lubricant sumpoverall. The lubricant present in the housing interior during operationcan thus be used to dampen the spring elements.

This occurs in particular as a result of the casing element of thereceiving element, which casing element prevents, at least to thegreatest possible extent, a draining of lubricant that has collected inthe receiving volume of the receiving element into the lubricant sumpfrom the receiving element. In this sense, a draining of lubricant fromthe receiving element is prevented to the “greatest possible extent” ifthe degree of leak-tightness of the receiving element ensures that anyoutflow of lubricant from the receiving element, for example throughporosities in the wall element, is not greater than the constant inflowof lubricant into the receiving element, which is open in the directionof the compressor/motor unit, which inflow is caused by the lubricantwhich spurts about the housing interior during operation of thecompressor and which drains out of the compressor/motor unit. Thus,lubricant that drips off or drains out of the compressor/motor unit ofthe compressor and collects in the receiving volume of the receivingelement initially remains in the interior of the receiving element andis hindered from exiting the receiving volume in the direction of thelubricant sump by the casing element of the receiving element. Becausethe receiving element protrudes past the sump height of the lubricantsump with its casing element in a vertical direction, the level oflubricant inside the receiving volume of the receiving element is, basedin each case on a common reference point, considerably higher than inthe lubricant sump.

This elevated level of the viscous lubricant (and oil) in the region ofthe spring elements ensures that the damping effect of the lubricantdescribed at the outset can be optimally utilized, since a significantlylarger vertical section of the spring elements can be placed underlubricant than is the case with known compressors, in which the heightof the lubricant sump is limited by the factors also mentioned at theoutset, in particular by the arrangement of the compressor/motor unit.As a result, an optimal damping of the spring elements can be achievedin the event of deflection, compression or expansion of the springelements, and the noise emission caused by the vibration transmission ofthe spring elements can be considerably reduced. In addition, potentialcollisions between the receiving element and the compressor/motor unit,more precisely between the spring holder of the receiving element and anadditional spring holder of the compressor/motor unit, which additionalspring holder serves to secure the respective spring element to thecompressor/motor unit and protrudes sectionwise into the spring element,are damped by a film of lubricant located between said parts.

Through a radial spacing of all other spring coils from the casingelement of the receiving element except for first spring coils of therespective spring element as viewed in a vertical direction, which firstspring coils can be embodied by the one, two or three spring coils ofthe spring element that are closest to the mounting region, it isensured that the respective spring element is entirely surrounded on theoutside thereof by lubricant, at least in the region of the other springcoils thereof. The damping effect described above is thus furtherenhanced. In this case, both the first spring coils and also the otherspring coils of the spring element are located in the receiving volumeof the receiving element in an operating state of the compressor,wherein in this operating state only the weight of the compressor/motorunit acts on the at least one spring element. Radial spacing of thespring coils from the casing element is thereby used to denote thedistance that is perpendicular to the vertical direction and extendsbetween the spring coils that are surrounded within the receivingelement, and thus by the casing element, and the casing element.

In a preferred embodiment of the compressor according to the invention,it is provided that a minimum clear inner diameter of the casing elementis larger than a maximum outer diameter of the spring element, so thatall spring coils arranged within the receiving volume for the respectivespring element are radially spaced from the casing element of therespective receiving element.

In this case, the spring element can be surrounded by lubricant in theregion of the entire vertical section thereof extending inside thereceiving element. In this embodiment of the compressor according to theinvention, it is in particular provided that the first spring coils—andtherefore all spring coils arranged within the receiving element—of therespective spring element are also spaced from the casing element.Movement of the spring is thus, at least in the case of smalleramplitudes, not impeded by the casing element. Collisions between thespring coils and the casing element of the receiving element areprevented to the greatest possible extent in compressors embodied inthis manner. Particularly in connection with receiving elements that areembodied to be rigid, for example those made of metal, a considerablenoise reduction can thus be achieved.

In another preferred embodiment of the compressor according to theinvention, it is provided that, in the aforementioned operating state ofthe compressor, in which operating state the at least one spring elementis loaded only with the weight of the compressor/motor unit, at leastthe first three spring coils (21, 22), preferably 50% of the springcoils, particularly preferably more than 70% of the spring coils, of thespring element lie within the receiving volume (32) of the respectivereceiving element (15, 16, 17, 18).

It is thus ensured that the lubricant collecting in the receiving volumecan reach a level that is particularly beneficial for damping purposesin relation to the height of the spring element. In the preferredembodiment of the compressor, the lubricant level in the receivingvolume is raised such that, even in the case of complete compression ofthe spring element, no spring coils of the spring element collide withone another outside of the receiving element—and therefore outside ofthe lubricant. All collisions taking place between spring coils are thusdamped by the lubricant present in the receiving element. In thismanner, an additional reduction of the noise emission is achieved.

In a preferred embodiment of the invention, it is provided that at leasttwo of the spring coils of the respective spring element that lie withinthe receiving volume are spaced apart from one another such that aspring travel extends between them.

As a result, the damping effect achieved with the lubricant can beutilized even more efficiently.

In the aforementioned operating state of the compressor, the springelement is particularly preferably arranged within the receiving volumeat least up to and including a transition region between active andpassive spring coils. The non-spaced spring coils are thereby understoodas being passive, and the spring coils spaced apart from one another areunderstood as being active.

Since the damping effect caused by the lubricant located in thereceiving volume in the operating state of the compressor is thestrongest in this transition region, an enhanced damping is achievedwith such embodiments of the compressor according to the invention.

In another preferred embodiment of the compressor according to theinvention, it is provided that the receiving element comprises arod-like spring holder protruding from the receiving element in avertical direction, via which spring holder the spring element isconnected by the inner side thereof to the receiving element in a forcefit.

With the spring holder of the receiving element, which spring holder istypically embodied as a securing pin with a diameter that tapers in avertical direction, a particularly simple and at the same time reliablesecuring of the spring element to the receiving element—and therefore tothe mounting region—is enabled. Especially if the spring element isembodied as a helical spring, a particularly simple and reliable fixingof the spring element to the receiving element can be achieved bysliding the helical spring onto the spring holder, provided that thediameter of the spring holder is matched to an inner diameter of thehelical spring. The spring holder can thereby be embodied in one piecewith a base element and the casing element of the receiving element, andcan be pulled with a hollow inner section onto a raised piece of thecompressor housing arranged in the base region, in order to secure thereceiving element to the compressor housing. Alternatively, thereceiving element can comprise an opening in the base element thereofembodied in one piece with the casing element, through which opening arod-like part of the compressor housing protruding in a verticaldirection from the base region extends into the receiving element. Insuch a case, the opening is matched to the protruding part of thecompressor housing such that a leakage of lubricant from the receivingelement is not possible, or is prevented to the greatest possibleextent, in the region in which the protruding part and the openingcontact one another.

In another embodiment of the invention, the base element can be formedby the mounting region of the compressor housing.

Particularly preferred is a further embodiment of the compressoraccording to the invention, in which embodiment the casing elementprotrudes past the spring holder of the receiving element in a verticaldirection.

As a result, a maximization of the receiving volume of the receivingelement for lubricant is achieved so that the receiving volume canaccommodate multiple spring coils.

In order to reduce that portion of noise emission which can beattributed to the collision between the deflected spring element and thecasing element of the receiving element, it is provided in anotherpreferred embodiment of the invention that the casing element of thereceiving element is embodied to be elastic.

In relation thereto, it is particularly advantageous if, as is providedin another preferred embodiment of the compressor according to theinvention, at least the casing element, but preferably the entirereceiving element, is made of an elastomer, particularly preferably of afluoroelastomer. This material results in an increased service life ofthe receiving element, which is exposed on a sustained basis toextremely high temperatures and the lubricant itself during theoperating state of the compressor.

In a particularly preferred embodiment of the compressor according tothe invention, it is provided that a clear inner diameter of the casingelement increases monotonically as viewed in a vertical direction,namely the clear inner diameter increases within the meaning of amonotonically increasing function of the vertical direction.

On the one hand, the receiving volume of the receiving element, in whichreceiving volume lubricant collects and can help dampen the springelement, is further increased by this measure. On the other hand, thefact that the amplitude of deflection of the spring element increases inthe vertical direction is thus taken into account. It is thus ensuredthat the spring element does not contact the casing element, even in thecase of extreme deflections of the spring element, for example duringthe start/stop process of the compressor/motor unit of the compressor.This is also accompanied by the reduction of that portion of the noiseemission which is due to the collision between the deflected springelement and the casing element of the receiving element, which casingelement is made of metal, for example.

It can be particularly advantageous if the casing element of thereceiving element, which casing element surrounds the spring element andpossibly the rod holder in a sleeve-like manner, is curved significantlyoutwardly at the end region thereof facing away from the compressorhousing. To achieve the volume increase of the receiving element thataccompanies a casing element embodied in such a manner, it is providedin another preferred embodiment of the compressor according to theinvention that the casing element, as viewed in a cross-section runningparallel to the vertical direction, has, at least sectionwise, the shapeof a circular arc, wherein a circle corresponding to said circular archas its center outside of the receiving element.

In a particularly preferred embodiment of the compressor according tothe invention, it is provided that the casing element comprises a firstvertical section and a second vertical section, wherein the firstvertical section and the second vertical section each extend in avertical direction, wherein a first clear inner diameter of the casingelement is constant in the region of the first vertical section andwherein the second vertical section of the casing element comprises adiameter expansion.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in greater detail with the aid ofexemplary embodiments. The drawings are by way of example and areintended to demonstrate, but in no way restrict or exclusively describe,the inventive concept.

In this matter:

FIG. 1 shows a sectional view of a compressor according to the invention

FIG. 2 shows a detailed view from FIG. 1

FIG. 3 shows an embodiment of a receiving element according to theinvention together with a spring element

FIG. 4 shows a top view of the housing base of the compressor from FIG.1 with four receiving elements and associated spring elements

WAYS OF EMBODYING THE INVENTION

FIG. 1 shows a coolant compressor in a sectional view, wherein thesection runs through the compressor housing 1 of the compressor. In ahousing interior 2 surrounded by the compressor housing 1, acompressor/motor unit 4 is arranged which primarily comprises a motor 8and a cylinder 5 for compressing coolant, wherein the coolant can flowinto the housing interior 2 via an inlet in the compressor housing 1.

Via a connecting rod, a crankshaft 7 driven by the motor 8 is inoperative connection with a piston 6 arranged in the cylinder 5 so thatthe rotation of the crankshaft 7 results in a periodic linear movementof the piston 6 between two dead centers of the cylinder 5.

On a base region of the compressor housing 1 serving as a mountingregion 34 of the compressor/motor unit 4, four receiving elements 15,16, 17, 18 are provided (see FIG. 4), of which only the receivingelements 15 and 16 can be seen in FIG. 1. The receiving element 15 isthereby fabricated in one piece and comprises a base element 28 incontact with the mounting region 34, a casing element 20 adjoining thebase element 28, and a spring holder 19 protruding from the base element28 in a vertical direction 23. The receiving element 15 is therebypulled onto a raised piece 29 of the compressor housing 1 with a hollowspace of the spring holder 19, whereby the receiving element 15 isconnected to the compressor housing 1 in a force fit. The casing element20 encloses the spring holder 19 and a receiving volume 32 of thereceiving element 15, which receiving volume 32 is formed between thespring holder 19 and the casing element 20, on the circumference or in asleeve-like manner. The casing element 20 protrudes past the springholder 19 in the vertical direction 23 (see also FIG. 2).

FIG. 2 is a detailed view of the receiving element 15. It can thereby beseen that a level of the lubricant 9 inside the receiving volume 32 ofthe receiving element 15 is noticeably higher than in a base region ofthe compressor housing 1, where a lubricant sump 30 forms during theoperation of the coolant compressor as intended, the maximum sump height14 of which lubricant sump 30 is, however, limited by the position ofthe compressor/motor unit 4. According to the invention, this isachieved in that the casing element 20 of the receiving element 15protrudes past the sump height 14 of the lubricant sump 30 in thevertical direction 23. The five spring coils, which are arranged withinthe receiving volume 32, of the spring element 10 embodied as a helicalspring, which spring element 10 is slid onto the spring holder 19 of thereceiving element 15 for the purpose of securing and is fixed in thisposition in a force fit, are thus surrounded by lubricant 9, whereby adamping of the vibrations caused by the compressor/motor unit 4 andtransmitted to the compressor housing 1 via the spring element 10 isachieved. For the purpose of securing the spring element 10 to thereceiving element 15, the spring element 10 is slid onto the springholder 19 of the receiving element and connected thereto in a force fit.Analogously, the spring element 10 is connected to the compressor/motorunit 4 via an additional spring holder 33 of the compressor/motor unit4.

In FIG. 2, the casing element 20 surrounds the spring holder 19 of thereceiving element 15 in a sleeve-like manner and has the same clearinner diameter when viewed across its entire height. In this embodiment,all spring coils of the spring element 10 embodied as a helical springthat are arranged within the receiving element 15 contact the casingelement 20. In embodiments of the coolant compressor in which thereceiving elements are made of an elastomer, preferably of afluoroelastomer, this noise-reduction effect is particularly pronounced,since this material exhibits the flexibility necessary therefor and alsowithstands on a sustained basis the high temperatures and the constantcontact with lubricant 9.

In contrast to the receiving element 15 shown in FIG. 2, in FIG. 3 onlyfirst spring coils 21 of the spring element 10—in this case: the firstand second coils—are in contact with the casing element 20 of thereceiving element 15 illustrated in FIG. 3, so that other spring coils22 of the spring element 10, which other spring coils 22 are locatedfarther away from the mounting region 34 of the compressor housing 1than the first spring coils 21, are radially spaced from the casingelement 20 of the receiving element 15.

For the purpose of the present invention, radial spacing is to beunderstood as meaning a distance perpendicular to the verticaldirection, that is, the direction in which the spring element 10 andpossibly the spring holder 19 protrude from the receiving element 15,between a spring coil arranged within the receiving volume 32 and thesection of the casing element 20 arranged at the same height as therespective spring coil.

In addition, the spacing of the other spring coils 22—in this case: thethird, fourth, and fifth coils—from the casing element 20 results in anadditional reduction in noise emission by the coolant compressoroverall, since noises that would be caused by the collision of thespring element 10 with the casing element 20 can be prevented to thegreatest possible extent.

The casing element 20 of the receiving elements 15 from FIG. 3 comprisesa first vertical section 25 arranged such that it runs in the verticaldirection 23 and a second vertical section 26 which is arranged suchthat it also runs in the vertical direction 23. A first clear innerdiameter 27 of the casing element 20 embodied in a sleeve-like manner isconstant over the entire first vertical section 25. In its secondvertical section 26, however, the casing element 20 comprises a diameterexpansion 24 proceeding continuously from the first clear inner diameter27 all the way to a maximum clear inner diameter 31 that is reached atthe upper end of the casing element 20. It is thus ensured that thespring element 10 also cannot collide with the casing element 20 in theevent of significant deflections.

FIG. 4 shows a top view of a base region of the compressor housing 1.The receiving elements 15, 16, 17, 18 are arranged in one mountingregion 34 each of the compressor housing 1. Each receiving element 15,16, 17, 18 thereby keeps one spring element 10, 11, 12, 13 arranged.Together, the receiving elements 15, 16, 17, 18, which can be embodiedaccording to the embodiments described above, and the spring elements10, 11, 12, 13 arranged therein form a mounting system 3 for thecompressor/motor unit 4 of the compressor.

LIST OF REFERENCE NUMERALS

-   1 Compressor housing-   2 Housing interior-   3 Mounting system-   4 Compressor/motor unit-   5 Cylinder-   6 Piston-   7 Crankshaft-   8 Motor-   9 Lubricant-   10, 11, 12, 13 Spring element-   14 Sump height-   15, 16, 17, 18 Receiving element-   19 Spring holder-   20 Casing element-   21 First spring coil-   22 Other spring coils-   23 Vertical direction-   24 Diameter expansion-   25 First vertical section-   26 Second vertical section-   27 First clear inner diameter-   28 Base element-   29 Raised piece-   30 Lubricant sump-   31 Maximum clear inner diameter-   32 Receiving volume-   33 Additional spring holder of the compressor/motor unit-   34 Mounting region

1. A compressor for compressing coolant circulating in a coolingcircuit, comprising a compressor housing enclosing a housing interior ofthe compressor, a compressor/motor unit which comprises at least onepiston, which moves in a cylinder, and a motor, at least one springelement, preferably multiple spring elements, via which spring elementthe compressor/motor unit is attached in an elastically mounted mannerto a mounting region of the compressor housing, preferably to a baseregion of the compressor housing, and at least one receiving elementarranged on the mounting region for the at least one spring element,preferably one receiving element for one spring element each, whereinthe respective spring element is accommodated in the receiving element,wherein the receiving element comprises a base element, which isconnected to the mounting region and from which the spring elementprotrudes in a vertical direction, a casing element, which casingelement surrounds the spring element in a sleeve-like manner, and areceiving volume bounded by the base element and the casing element, inorder to enable a collection of lubricant in the receiving volume, sothat a section of the spring element that is arranged in the receivingvolume is enveloped by lubricant in the operating state of thecompressor, wherein the casing element protrudes past a sump height of alubricant sump in the vertical direction, which lubricant sump forms inthe housing interior in the operating state of the compressor.
 2. Thecompressor according to claim 1, wherein a minimum clear inner diameterof the casing element is larger than a maximum outer diameter of thespring element.
 3. The compressor according to claim 1, wherein, in anoperating state of the compressor, in which operating state the at leastone spring element is loaded only with the weight of thecompressor/motor unit, at least the first three spring coils, preferably50% of the spring coils, particularly preferably more than 70% of thespring coils, of the spring element lie within the receiving volume ofthe respective receiving element.
 4. The compressor according to claim3, wherein a spring travel extends between at least two of the springcoils of the respective spring element that lie within the receivingvolume in the aforementioned operating state of the compressor.
 5. Thecompressor according to claim 1, wherein the receiving element comprisesa rod-like spring holder protruding from the receiving element in thevertical direction, via which spring holder the spring element isconnected by the inner side thereof to the receiving element in a forcefit.
 6. The compressor according to claim 5, wherein the casing elementprotrudes past the spring holder of the receiving element in a verticaldirection.
 7. The compressor according to claim 1, wherein the casingelement of the receiving element is embodied to be elastic.
 8. Thecompressor according to claim 1, wherein at least the casing element,but preferably the entire receiving element, is made of an elastomer,particularly preferably of a fluoroelastomer.
 9. The compressoraccording to claim 1, wherein a clear inner diameter of the casingelement increases monotonically as viewed in the vertical direction. 10.The compressor according to claim 9, wherein the casing elementcomprises a first vertical section and a second vertical section,wherein the first vertical section and the second vertical section eachextend in the vertical direction, wherein a first clear inner diameterof the casing element is constant in the region of the first verticalsection and wherein the second vertical section the casing elementcomprises a diameter expansion.
 11. The compressor according to claim 9,wherein the casing element, as viewed in a cross-section runningparallel to the vertical direction, has, at least sectionwise, the shapeof a circular arc, wherein a circle corresponding to said circular archas its center outside of the receiving element.